Anderson is taking a new approach to the director of photography role on his mysterious new project.

When Focus Features announced in February that production began in the U.K. on Paul Thomas Anderson’s new film, one notable role wasn’t on the production’s creative roster: director of photography. It’s not unusual for Anderson’s movies to be shrouded in secrecy, with crew members required to sign non-disclosure agreements, but in this case the answer hid in plain sight: Anderson worked as his own DP.

What will be Daniel Day-Lewis’ last movie was known as “Phantom Thread” during production, but that will not be the title when the film hits theaters Christmas Day, IndieWire has learned. Written and directed by Anderson, the movie set in 1950s London stars Day-Lewis as a dressmaker commissioned by royalty and high society.

Anderson toyed with the idea of working as both director and DP on one of his movies for years, according to sources familiar with the situation. (Anderson was not available for comment Wednesday.) Last year, he served as both director and DP on three music videos for Radiohead. According to a crew member who worked on “Inherent Vice” and “The Master,” Anderson’s knowledge of cinematography grew while working with DP Robert Elswit, who shot six of Anderson’s previous seven films and won the Oscar for best cinematography for “There Will Be Blood.”

“Paul has learned a lot from director of photography Robert Elswit and gaffer Michael Bauman,” said lighting cameraman Michael Gerzevitz. Bauman worked as a gaffer on Anderson’s last three movies, including his upcoming film. One source said Anderson originally had Elswit in mind to shoot the movie, but that the DP was unavailable due to scheduling conflicts.

Paul Thomas Anderson during production of “Inherent Vice”

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Matthew Mebane, a member of the camera department on “Inherent Vice” and “The Master,” said the amount Anderson knew about film stock and camera lenses immediately caught him off guard. “He knew not just the focal length, but the actual characteristics of that particular brand of lens,” Mebane said. “He honestly was the most camera-savvy director I’ve ever worked with, and that was apparent right off the bat.”

Other directors who have opted to serve as their own DP include David Lynch (“Inland Empire”), Doug Liman (“Go”), Robert Rodriguez (“Sin City”) and Quentin Tarantino (“Death Proof”). Steven Soderbergh shot more than a dozen of his own movies, including his upcoming “Logan Lucky,” which hits theaters in August. Cinematographer-turned-director Reed Morano also did double duty on her feature debut, “Meadowland,” and her recently wrapped second film, “I Think We’re Alone Now.”

“It’s an incredibly difficult position to be in,” said “Donnie Darko” cinematographer Steven Poster, ASC, who also serves as president of the International Cinematographers Guild. “You have to be a very special person to be able to do it.” Though unconventional, eliminating the division of labor between director and DP can work for certain filmmakers, according to Gerzevitz.

“I think itworks in yourfavor if you know lenses and cameras on how to tell a visual story,” he said. Gerzevitz added that Anderson’s preference for using film rather than digital photography is based on a “love for the medium.” During production on “The Master,” when a piece of damaged film was handed to Anderson, he held it up to Gerzevitz’s nose. “The old-nitrite smell was all I needed to get his point,” Gerzevitz said.

Paul Thomas Anderson and Daniel Day-Lewis on the set of “There Will Be Blood.”

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Of course, Anderson still had a large team of collaborators to shape the visual style of his new movie. IMDb lists 15 people in the camera and electrical departments, with the core team including Bauman, an assistant cameraman, key grip, and camera operator. Anderson also operated the camera for certain shots, as he did on films including “The Master” and “Inherent Vice.”

One thing that sets Anderson apart from other directors is how much time and effort he spends testing camera lenses, according to a source working on the new project who requested anonymity due to a confidentiality agreement. “He’s just so technically inclined,” the person said, adding that although Anderson likely has a “broader knowledge base” than most directors when it comes to cinematography, he would never want to labeled as a cinematographer, and is self-deprecating about his lack of cinematographic expertise.

Prior to his most recent movie, the only other film on which Anderson had a DP credit was his 1988 short, “The Dirk Diggler Story.” Six years later, while workshopping his first feature “Hard Eight” as a fellow at the Sundance Institute’s feature film program, Poster was one of the 23-year-old director’s advisors. “I was so impressed with his ability at his age to see what he saw and to put it down on film,” Poster said. “It was a joy to work with him.”